Segment Information Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 224,910		$ 213,370	$ 442,010		$ 413,200
Operating profit (loss)	31,520		26,420	66,730		42,330
Operating Segments [Member] | Packaging [Member]
Segment Reporting Information [Line Items]
Net sales	95,090		88,740	183,290		169,700
Operating profit (loss)	22,810		21,590	42,390		38,490
Operating Segments [Member] | Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales	45,620		47,580	91,430		93,000
Operating profit (loss)	7,310		6,990	12,390		12,050
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales	84,200		77,050	167,290		150,500
Operating profit (loss)	9,240		5,260	18,890		6,770
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating profit (loss)	$ (7,840)		$ (7,420)	$ (6,940)	[1]	$ (14,980)
Selling, General and Administrative Expenses [Member]
Segment Reporting Information, Additional Information [Abstract]
Loss Contingency Accrual, Period Increase (Decrease)		$ (8,200)

[1] During the first quarter of 2018, the Company removed an obligation from its balance sheet, resulting in an approximate $8.2 million non-cash reduction in selling, general and administrative expenses. See Note 10, "Commitments and Contingencies," for further details.